NEMA 17 vs 28BYJ-48: Which Stepper Motor Do You Need?
One drives 3D printers, the other powers tiny paper contraptions. Learn the vast differences in their torque and precision.
NEMA 17
The NEMA 17 is a heavy-duty, powerful stepper motor that serves as the workhorse for virtually all desktop 3D printers and CNCs.
28BYJ-48
The 28BYJ-48 is a tiny, incredibly cheap, geared unipolar stepper motor often sold with a ULN2003 driver board.
Specifications Comparison
| Specification | NEMA 17 | 28BYJ-48 |
|---|---|---|
| Type | Bipolar Stepper | Unipolar (Geared) |
| Step Angle | 1.8 degrees (200 steps/rev) | 5.625 degrees (64 steps/rev natively, 4096 geared) |
| Operating Voltage | 12V - 24V typical | 5V |
| Holding Torque | Upto 4.2 kg-cm | ~0.3 kg-cm |
| Current/Phase | 1.2A - 1.7A | ~200mA |
| Weight | ~280g | 35g |
| Price (India) | ₹450 - ₹700 | ₹90 - ₹150 (with driver) |
NEMA 17
Pros
- Massive holding torque, capable of moving heavy extruders and CNC gantries
- Extremely high precision and repeat-ability
- Industry standard size, making it easy to find mounts and brackets
- Very durable and designed for thousands of hours of continuous operation
Cons
- Requires an external driver (like A4988) and a dedicated 12V+ power supply
- Heavy and physically large
- Overkill for simple aesthetic projects (like opening a tiny door)
28BYJ-48
Pros
- Incredibly cheap and often bundled with its own driver board ready to use
- Runs directly off 5V (can be powered from Arduino 5V pin under light load)
- Internal gearing gives it high resolution for very slow, precise movements
- Lightweight and easy to embed inside small toys or clocks
Cons
- Very weak torque; cannot lift heavy objects
- Very slow top speed due to internal 1:64 gear reduction
- Lots of internal gear backlash (slop) makes it poor for precision positioning (like 3D printing)
Our Recommendation
Choose the **NEMA 17** if you are building a 3D printer, CNC machine, robotic arm, or anything that requires real torque and precision. Choose the **28BYJ-48** for simple desk toys, automatic blinds, slow camera panning, or learning how stepper motors work on a budget.
The Verdict
They occupy completely different weight classes. The NEMA 17 is industrial, while the 28BYJ-48 is for light desktop hobbies.